I was introduced to the term "gaslighting" today.
According to Wikipedia "Gaslighting or gas-lighting is a form of mental abuse in which a victim is manipulated into doubting their own memory,perception, and sanity. Instances may range from the denial by an abuser that previous abusive incidents ever occurred, up to the staging of bizarre events by the abuser with the intention of disorienting the victim."
The term originates from a 1938 play (and film adaptions) "Gas Light" where a husband tries to convince his wife and others that she is insane. It has since been used colloquially to "describe efforts to manipulate someone's sense of reality."